Pivoted member assembly

ABSTRACT

This invention relates to pivoted member assemblies and has as its primary object the provision of an improved pivoted member assembly in which the pivoted member can be held by friction in a selected position despite vibrations to which its mounting is exposed in service.

inventor Virgil l... lFrnmz Salem, Wn. Appl. No. llJ-ii Filed Urt. 22,i985 Patented Sept. 7, 197i Assignee Graham-White Sales CorpomtionSalem, Vm. Continumtion oi applition Ser. No. A3,(36, .lluly 115, i960,now almndolmed.

PIT/@TMB MEMBER ASSEMBLY 5 Elimina, l5 Drawing Figs.

IUE. CII 2A8/4l79, 16/140, 248/289 limit. CII Bom ll/ii Tied ofSmil-elli 16/40, 151, 168; 88/86, 87, 92, 93, 96, 97, 98; 20/16; 189/46;98/106; 248/479, 289

[5 6] Reierences Cited UNlTED STATES PATENTS 90,330 5/1869 Wolters16/168 735,481 8/1903 Ek 16/140 743,279 l H1903 Haycock 16/168 2,146,3912/l939 Anderson l6/l40 2,698,958 I/l955 Adams 16/140 FOREIGN PATENTS105,113 4/1917 Great Britain 16/14 Primary Examiner-David SchonbergAssistant Examiner-Ronald J. Stern Attorney-Wilmer Mechlin ABSTRACT:This invention relates to pivoted member assemblies and has as itsprimary object the provision of an irnproved pivoted member assembly inwhich the pivoted member can be held by friction in a selected positiondespite vibrations to which its mounting is exposed in service.

PATENTE SEP 7197i sum1 0F 3 FIG. l

FIG. 3

FIG. 2

Inventor: Virgili L. Frantz FIG. 4

his Attorney PMENTED SEP 1 :en

SHEEI 2 BF 3 PIG.. 6

lnve Mor: Vi'yqgl L. Franw his Attorney,

PIVOTEID MEMBER ASSEMBLY This application is a continuation of mycopending application Ser. No. 43,036, filed July l5, i960 nowabandoned.

Another object of the invention is to provide a friction mounting for apivoted member whereby play in the pivotal connection between the memberand the support on which it is mounted is effectively eliminated.

An additional object of the invention is to provide a friction mountingfor a pivoted member which is readily adjustable in the frictionrestraining pivoting of the member to meet the requirements of aparticular installation.

A further object of the invention is to provide a pivoted memberassembly wherein the pivoted member has a framed glass or like plate,the frame of which is readily disassemblable for replacement of the platbut is blocked from accidental disassembly by the pivotal mounting.

Another object ofthe invention is to provide in a pivoted memberassembly a disassemblable frame, the disassembly of which is facilitatedby one or more parts capable of backing itself` off from another part asit is disconnected therefrom.

Another object of the invention is to provide a friction mounting for apivoted member which not only is adjustable in friction but is proofagainst change in the adjustment by either service vibrations orpivoting of the member.

A feature of the invention is the provision as a pivot of an adjustablefriction mounting for a pivoted member, of a tapered metal or otherrigid pin fitting into a correspondingly tapered socket in a bushing ofbrake lining or like material which effectively prevents the buildup ofvibrations in the member.

Other objects and features of the invention will appear hereinafter inthe detailed description, be particularly pointed out in theappendedclaims and be illustrated in the accompanying drawings in which:

FIG. l is a side elevational view of a preferred embodiment of thepivoted member assembly of the present invention;

FIG. 2 is a rear end elevational view of the assembly of FIG. Il;

FIG. 3 is a front end elevational view of the assembly of FIG. l;

FIG. 4 is a plan view of the assembly of the preceding figures;

FIG. 5 is a fragmentary vertical sectional view on an enlarged scale,taken along lines S-S of FIG. 4l;

F IG. 6 is a fragmentary horizontal sectional view taken along lines 6 6of FIG. S;

F IG. '7 is a fragmentary horizontal sectional view taken along lines7-7 of FIG. 5;

FIG. d is a fragmentary horizontal sectional view taken along lines ofFIG. 5;

FIG. 9 is a fragmentary horizontal sectional view taken along lines 9-9of FIG. S;

FIG. l is a fragmentary vertical sectional view taken along lineslltl-llll ofFIG.

FIG. lll is a side elevational view of another embodiment of the pivotedmember assembly of the present invention;

FIG. l2 is a rear end elevational view of the assembly of FIG. Il;

FIG. llll is a horizontal sectional view on an enlarged scale takenalong lines l3-ll3 of FIG. Il;

FIG. Ml is a fragmentary horizontal sectional view on the scale of FIG.13, taken along lines 14-14 of FIG. Il; and

FIG. )l5 is a fragmentary horizontal sectional view on the scale of FIG.ll3, taken along lines ll5-l5 of FIG. lll.

Referring now in detail to the drawings in which like referencecharacters designate like parts, the improved pivoted member assembly ofthe present invention may be used to provide a windshield wing, a frontor rear quarter window, a rearview mirror or any other member designedfor pivotal mounting on part of a vehicle or other support and to beheld by friction in any of a plurality of angularly related positions inwhich it is set, despite vibration of thesupport in service. Asexemplary of the invention, the assembly of each of the illustratedembodiments is of a type particularly suited for use as a windshieldassembly on a locomotive, the as sembly of the second embodiment alsoincluding, as a subassembly, an exemplary rearview mirror assembly.

Considering first the embodiment of FIGS. l-llI), the pivoted memberassembly there illustrated is comprised of a windshield wing or otherpivoted member 1, which may be of one piece or unitary, but ordinarilywill include a transparent or mirror plate 2 of glass or other suitablematerial and a frame 3 mounting and partly or entirely surrounding orframing the plate. Made of anodized aluminum, stainless steel or othermaterial suitable for the particular environment in which it is to beused, the illustrated frame 3 is constructed of a plurality or, moreexactly, a multiplicity of pieces or parts detachedly or removablyconnected to each other to facilitate application or removal of theplate 2.

In this first embodiment, the frame 3 is open at the rear and formed ofthree pieces, parts or elements, one a vertically extending frontpiece 4and the others horizontally extending upper and lower, top and bottom orendpieces 5 and 6, respectively, the latter overlying and embracing orincluding the extremities of the frontpiece. ln assembled relation theseveral pieces 4, 5 and 6 are interrupted along their inner edges 7 by acontinuous channel or groove 8 in which the plate 2 seats or isreceived, the groove preferably having a rubber or like resilient liningor padding to protect the plate against breakage and being partly closedat the rear by intumed or instanding rear legs 9 of the upper and lowerpieces. To maintain or hold them against angling relative to thefrontpiece 4, each of the upper and lower pieces 5 and 6 preferably hasa tongue and groove or like antirotational joint or interfit l0 betweenits intumed or instanding front leg Il and the adjoining or contiguousend or extremity l2 of the frontpiece. The releasable interlock orattachment between the endpieces 5 and 6 and the frontpiece 4 is hereprovided by a pair of bolts 13, each slidably received or fitting in abore I4 in the front leg l1 of one of the end pieces and threadedlyengaged or received in an axially aligned or concentric bore l5 in theadjoining end l2 and extending longitudinally of the frontpiece.

So mounting or supporting the plate 2, the pivoted member ll ispivotally mounted on a window frame or other suitable part (not shown)of the vehicle or other support to which it is applied by a pair ofcoaxial pivots I6 which usually will be axi ally spaced and, here,conveniently connect to the endpieces 5 and 6 above and below and inlongitudinal alignment with the frontpiece 4. Each of these pivots I6has as its essential components a pivot pin or stud of stainless steelor other suitable rigid material and one or more friction bushings,plugs or blocks ll7, each having an inwardly tapered or conical andpreferably frustoconical recess, aperture or seat I8 rotatably receivingor seating a correspondingly outwardly tapered end 19 of the associatedpivot pin. Each bushing 17 surrounds or encircles and is of greaterdepth than the received end 19 of the associated pin, thus separating orspacing and so serving as the only contact or connection between the pinand the member or part in which the bushing is socketed.

Any play in the pivotal connection between a windshield wing or likepivoted member and the part on which it is mounted will cause the memberto vibrate excessively under forces on or transmitted to it and suchvibration in turn will produce rapid wear in the connection and furtheraggravate the condition. Play is necessary in a pivotal connection inwhich there is metal-to-metal contact between the relatively pivotingelements to avoid galling or seizing of the metal, but in the connectionof this invention play is prevented by the tapered fit between each pinand bushing, by the containment of the pin ends in the associatedbushings and by making the bushings of a material combining toughnessand resilience with a high coefficient of friction. Of the materialspossessing these characteristics, brake lining material is preferred,its high frictional coefficient and resiliency accommodating a widerange of adjustment in the frictional drag or resistance to pivoting ofthe pivoted member, while its toughness and wearresistance assure longservice life.

While each of the pivots 16 includes a pivot pin and a friction bushing,the pivots preferably are not identical. lnstead, the lower or bottompivot pin 20 preferably is a double-ended pin, the opposite tapered ends19 of which each fits in the correspondingly tapered aperture or seat 18in the friction bushing 17, Of the two bushings 17 used in the lowerpivot 16, one is carried by or connected or attached to the pivotedmember l and the other is correspondingly associated with an adjoiningpart (not shown) of the vehicle or other support (not shown) on whichthe assembly is pivotally mounted. Depending on the installation, thesupport-attached bushing of the lower pivot may be mounted directly onthe support part. However, in the exemplary installation in which it isused as a locomotive windshield wing, the assembly, instead of beingmounted within a frame bounding a window opening, as are the quarterwindows of automobiles, is designed to be attached to the locomotive caboutside the opening. For such in stallation, the assembly includes notonly the pivoted member l and its pivots 16 but also upper and lowermounting brackets 2l and 22, each boltable or otherwise removablyattachable exteriorly to a corner post or like part (not shown) at aside of the windshield (not shown).

Conveniently, the lower mounting bracket 22 carries the lower frictionbushing of the lower pivot in an upwardly opening socket or pocket 23which conforms in cross section to the bushing and, for readyapplication and removal of the latter, preferably is of cylindrical orother uniform cross section, It also is preferred that the lowermounting bracket 22 have a bore or aperture 24 extending through it andcoaxial or concentric with the lower pivot pin 20, so that, in case ofneed during disassembly, that pivot pin can be dislodged from the lowerbushing by being tapped from below. The upper bushing of the lowerpivot, as well, preferably is seated in the member by which it iscarried and thus, here, seats in a socket or pocket 25 in and openingdownwardly from the lower endpiece 6 of the frame 3, this socket orseat, like the confronting socket or seat 23 in the lower bracket 22,snugly fitting its bushing, with the latter preferably cylindrical or ofother uniform cross section to facilitate its removal. While accessiblefrom below through the bore 24 in the lower bracket 22, the lower pivotpin 20 is not so accessible from above and, to facilitate its removalfrom the upper bushing, thus preferably has, substantially midway of itsends, about its, here, cylindrical midportion 26, an annular flange 27through which it can be pried from the upper bushing.

One of the pivots 16, here the upper pivot, is designed not only toserve as a pivot but also to enable the friction restraining swinging ofthe pivoted member 1 to be varied to suit the needs of a particularinstallation. Although this might be accomplished with a double-endedpivot pin such as that here used in the other or lower pivot, it ispreferred that the upper pivot pin 28 have a single tapered end 19 andthat the friction bushing for that pivot seat or fit snugly in anupwardly opening socket, pocket or seat 29 of correspondingconfiguration in the upper endpiece of the frame 3. ln lieu of a secondtapered end, the pivot pin 28 has as its opposite end an out-ofround,preferably square or rectangular head 30 which slidably fits or seats ina correspondingly rectangular or other wise out-of-round slot 31 in theupper mounting bracket 21. Opening downwardly and conveniently extendinghorizontally through the upper bracket 21, the slot 3l permits the upperpivot pin 28 to be slid or shifted axially relative to the bracket,while enabling the bracket to prevent rotation of the pin incident topivoting ofthe pivoted member l. This nonrotatable connection betweenthe upper pivot pin 28 and upper mounting bracket 21 effectivelyprevents any rotational or pivotal forces from being transmitted throughthe pin to an adjusting or capscrew 32 threaded from above through theupper bracket 21 in axial alignment or concentric with the pin andbearing against or engaging the upper surface or end 33 of the head 30,the adjusting screw 32, to hold the pin in correct axial alignment,preferably has a necked or relatively narrow cylindrical tip or lowerend portion 34 fitting in a correspondingly configured cavity 35 in theconfronting end of the head 30 and itself has a hex or like head 36suitable for wrench actuation. Preferably, the adjusting screw 32 islockable against rotation by a lock nut 37 encircling its threaded stem38 above the bracket 21.

Constructed in the above manner and with its several friction bushings17 identical for interchangeability, the pivoted member assembly isenabled on actuation of the adjusting screw 32 to vary the penetrationof the several tapered ends 19 of the pins 20 and 28 and, by virtue ofthe wedging action derivable from the taper of these ends, control thefriction engendered between the pivot pins and the friction bushings.Depending on the particular installation, the adjustment of the frictionin the mounting may be varied from one extreme at which the pivotedmember will pivot at the touch of a finger to the other in which themember is actually locked against rotation, This, coupled with theability of both pivots to be playfree, tight or snug over the range ofadjustment and thus prevent a buildup of vibrations in the pivotedmember, permits the pivoted member to be held against vibration or othermovement relative to its support in any pivoted position in which it isset, despite vibrations in the support and any wind or like pressure towhich it may be subjected n service.

lt was mentioned earlier that the bolts 13 by which the upper and lowerendpieces 5 and 6 of the frame 3 are connected to its front piece 4preferably are concentric with each other and extend longitudinally ofthe frontpiece. This preferred construction has purpose in facilitatingdisassembly of the frame 3 if, in addition, the bolts 13 are concentricwith the pivotal axis of the pivoted member 1, are inset in the frontlegs 1l of the endpieces S and 6 inside the bushing-receiving sockets 25and 29 therein and have their heads 29 of larger diameter or crosssection than the inner ends of the apertures 18 in the friction bushings17 fitting snugly in those sockets. Rotatable in the bores 14 in thefront legs l1 and with their heads 39 countersunk into the legs insidethe bushing-receiv ing sockets 25 and 29, the connecting bolts 13 arereleasably held against axial movement relative to the end pieces byengagement of their heads by the associated snug-fitting bushing 17.Also, while the apertures in the bushings are of less minimum crosssection than the heads 39 of the bolts, they are of ample crosssectionto receive an Allen" wrench or like means (not shown) for turning thebolts. Consequently, once it has been removed from its pivotal mounting,the frame can be disassembled by backing off the connecting bolts 13without removing the associated friction bushings 17 and the latter, byholding the bolts against axial displacement relative to the endpieces 5and 6, cause the backing off of the bolts automatically to back off orseparate the endpieces from the frontpiece 4.

Identical with the first embodiment in the pivotal mounting of thepivoted member 1 and in the interlock between the upper and lower pieces40 and frontpiece 41 of its frame 42 of the pivoted member, the pivotedmember assembly of the second embodiment shown in FIGS. 11-15 differsfrom the first mainly in including as a subassembly, a rearview mirrorassembly 43. Exemplary in its mirror assembly 43 of the mounting of apivoted member within a frame or like boundary, the pivoted member l ofthis embodiment has its frame 42 closed at the rear by a verticallyextending rear piece or part 44, overlapping and removably attached, asby bolting, to the rear ends of the upper and lower pieces 40. The spacewithin the frame 42 is here divided into upper and lower openings 45 and46, respectively, by a horizontally extending crosspiece, part orelement 47, held in position on assembly of the frame, conveniently bysupporting it on a U-shaped fillet 48 fitting in a groove 49 in thefront, side and rear pieces of the frame 42 at the sides and bottom ofthe lower opening. One of the openings, here the upper opening 45, maybe closed permanently by a glass or other transparent plate 50. Theother or lower opening 44 contains the mirror 5l of the mirror assembly43, the mirror preferably being of such size and so mounted on thecrosspiece 48 as to be adapted substantially to close and to swing orpivot through the lower opening 46. For mounting it on the crosspiece47, the mirror 5l here has a hinge lug 52 integral with and upstandingfrom its frame 53 and fitting into a downwardly opening recess 54 in andintermediate the ends ofthe crosspiece 47.

As does the mounting of the pivoted member l, that of the mirror 5l usesas its pivots 53 a pair of axially spaced, taper ended pivot pins, thetapered ends S6 of which fit into correspondingly tapered apertures orseats 57 in friction bushings S8 of brake lining or like suitableresilient material. Also, as in the main mounting, one ofthe pivot pinspreferably is a double-ended pin 57 and the other a square or likeout-of-round headed pivot pin 60. Of the several friction bushings 58,two are seated, socketed or received in opposite ends of the hinge lug52 on the mirror frame 53 and the third is correspondingly mounted in aconfronting end wall of the recess 54 in the crosspiece 47. The head 6lofthe headed pivot pin 60 rides in and is held against rotation by aguide slot 62, conveniently formed in the other end wall of the recess54 in the crosspiece 47 and the headed pin is shiftable to adjust thecompression and consequent friction between the pivot pins S9 and 60 andthe friction bushings 58 by an adjusting screw 63 which, by an cndinterfit with the head, also serves to maintain the headed pin in properalignment.

lnsertable and accessible for adjustment through an aperture 64 in oneof the front and rear pieces 4l and 43, here the rear piece, theadjusting screw 63 ofthe rearview mirror assembly 43 need not be lockedagainst loosening due to vibration, since it is protected from vibrationby the mounting of the pivoted member l. Preferably the frontpiece 4l ofthe frame 42 also is apertured in line with the pivotal axis of themirror 49 so that, if desired, the mirror assembly 43, including thecrosspiece 47, can be reversed for adjustment of the friction in themounting from the front rather than the rear of the frame. With itspivotal axis preferably angularly related and, here, normal to that ofthe pivoted member l, the mirror 51 in effect is universally connectedto the support for the main assembly and thus may be set at any desiredangle.

From the above detailed description, it will be apparent that there hasbeen provided an improved pivoted member assembly which is adjustable tohold a pivoted member by friction in any desired position and willmaintain that adjustment regardless of outside forces. lt should beunderstood that the described and disclosed embodiments are merelyexemplary of the invention and that all modifications are intended to beincluded that do not depart from the spirit of the invention or thescope of the appended claims.

Having described my invention, [claim:

l. A pivoted member assembly mountable on a support member, comprising apivoted member, a frame at least partially bounding said pivoted memberand including a sidepiece and an endpiece overlapping an end of andconnectable to said sidepiece, bolt means inset and rotatable in saidendpiece and threadedly engaging said sidepiece for releasablyconnecting said pieces, pivots pivotally connecting said pivoted andsupport members, each of said pivots including a rigid pivot pin and atough resilient nonmetallic friction bushing having an aperturereceiving an end of and separating said pin from one of said members,one of said bushings being releasably seated in said endpiece betweensaid connecting bolt means and the associated pivot pin for releasablyholding said bolt means against axial displacement relative to saidpiece while permitting access through its aperture of means for turningsaid bolt means.

2. A pivoted member assembly mountable on a support, comprising apivoted member, a frame at least partially bounding said member andincluding a sidepiece and a pair of endpieces overlapping ends of andconnectable to said side piece, pivots for pivotally mounting saidpivoted member on said support, each of said pivots including anapertured tough resilient nonmetallic friction bushing; seated in one ofsaid endpieces and a rigid pivot pin, each pin having an end received inand being spaced from its endpiece by one of said bushings, and a pairof bolts concentric with the pivot axis of said pivoted member and eachconnecting one of said endpieces to said sidepiece, said boltsthreadedly engaging said sidepiece and being rotatable in said endpiecesand inset therein inside said bushings, and said bushings engaging headsof and releasably holding said bolts against axial movement relative tosaid endpieces and through their apertures permitting access thereto ofmeans for turning said bolts.

3. A pivoted member assembly comprising a pivoted member, a frame atleast partially bounding said member and formed of a plurality ofreleasably connected pieces, bolts releasably connecting said pieces, apair of mounting bracket members attachable to a support, a pair ofpivots each pivotally connecting said pivoted member to one of saidbracket members, each of said pivots including a rigid pivot pin havinga tapered end and a tough resilient nonmetallic friction bushingapertured to receive said end and spacing said pin from and seating inone of said members connected by said pivot, certain of said bushingsseating in said endpieces each outside of and engaging a head of one ofsaid bolts for releasably holding said bolt against axial movementrelative to the associated endpiece, an out-of-round slot in one of saidbracket members nonrotatably receiving a correspondingly configured headof one of said pins, and an adjusting screw threaded into said onebracket in axial alignment with and having an end fitting into said headof said one pivot pin for adjusting the friction in said pivots whilemaintaining said one pin in alignment.

4. A pivoted member assembly comprising a pivoted member, a frame atleast partially bounding said member and formed of a plurality ofreleasably connected pieces, bolts releasably connecting said pieces, apair of mounting bracket members attachable to a support, a pair ofpivots each pivotally connecting said pivoted member to one of saidbracket members, each of said pivots including a rigid pivot pin havinga tapered end and a tough resilient nonmetallic friction bushingapertured to receive said end and spacing said pin from and seating inone of said members connected by said pivot, certain of said bushingsseating in said endpieces each outside of and engaging a head of one ofsaid bolts for releasably holding said bolt against axial movementrelative to the associated endpiece, an out-of-round slot in one of saidbracket members nonrotatably receiving a correspondingly configured headof one of said pins, an adjusting screw threaded into said one bracketin axial alignment with and engaging said head of said one pivot pin foradjusting the friction in said pivots, and means for locking saidadjusting screw in adjusted positionA 5. A pivoted member assemblycomprising a pivoted member, a frame at least partially bounding saidmember and formed of a plurality of releasably connected pieces, boltsreleasably connecting said pieces, a pair of mounting bracket membersattachable to a support, a pair of pivots each pivotally connecting saidpivoted member to one of said bracket members, each of said pivotsincluding a rigid pivot pin having a tapered end and a tough resilientnonmetallic friction bushing receiving said end and spacing said pinfrom and seating in one of said members connected by said pivot, certainof said bushings being seated in said endpieces each outside of andengaging a head of one of said bolts for releasably holding said boltagainst axial movement relative to the associated endpiece, anout-of-round slot in one of said bracket members nonrotatably receivinga correspondingly configured head of one of said pins, and an adjustingscrew threaded into said one bracket in axial alignment with and engaging said head of said one pivot pin for adjusting the friction in saidpivots.

1. A pivoted member assembly mountable on a support member, comprising apivoted member, a frame at least partially bounding said pivoted memberand including a sidepiece and an endpiece overlapping an end of andconnectable to said sidepiece, bolt means inset and rotatable in saidendpiece and threadedly engaging said sidepiece for releasablyconnecting said pieces, pivots pivotally connecting said pivoted andsupport members, each of said pivots including a rigid pivot pin and atough resilient nonmetallic friction bushing having an aperturereceiving an end of and separating said pin from one of said members,one of said bushings being releasably seated in said endpiece betweensaid connecting bolt means and the associated pivot pin for releasablyholding said bolt means against axial displacement relative to saidpiece while permitting access through its aperture of means for turningsaid bolt means.
 2. A pivoted member assembly mountable on a support,comprising a pivoted member, a frame at least partially bounding saidmember and including a sidepiece and a pair of endpieces overlappingends of and connectable to said sidepiece, pivots for pivotally mountingsaid pivoted member on said support, each of said pivots including anapertured tough resilient nonmetallic friction bushing seated in one ofsaid endpieces and a rigid pivot pin, each pin having an end received inand being spaced from its endpiece by one of said bushings, and a pairof bolts concentric with the pivot axis of said pivoted member and eachconnecting one of said endpieces to said sidepiece, said boltsthreadedly engaging said sidepiece and being rotatable in said endpiecesand inset therein inside said bushings, and said bushings engaging headsof and releasably holding said bolts against axial movement relative tosaid endpieces and through their apertures permitting access thereto ofmeans for turning said bolts.
 3. A pivoted member assembly comprising apivoted member, a frame at least partially bounding said member andformed of a plurality of releasably connected pieces, bolts releasablyconnecting said pieces, a pair of mounting bracket members attachable toa support, a pair of pivots each pivotally connecting said pivotedmember to one of said bracket members, each of said pivots including arigid pivot pin having a tapered end and a tough resilient nonmetallicfriction bushing apertured to receive said end and spacing said pin fromand seating in one of said members connected by said pivot, certain ofsaid bushings seating in said endpieces each outside of and engaging ahead of one of said bolts for releasably holding said bolt against axialmovement relative to the associated endpiece, an out-of-round slot inone of said bracket members nonrotatably receiving a correspondinglyconfigured head of one of said pins, and an adjusting screw threadedinto said one bracket in axial alignment with and having an end fittinginto said head of said one pivot pin for adjusting the friction in saidpivots while maintaining said one pin in alignment.
 4. A pivoted memberassembly comprising a pivoted member, a frame at least partiallybounding said member and formed of a plurality of releasably connectedpieces, bolts releasably connecting said pieces, a pair of moUntingbracket members attachable to a support, a pair of pivots each pivotallyconnecting said pivoted member to one of said bracket members, each ofsaid pivots including a rigid pivot pin having a tapered end and a toughresilient nonmetallic friction bushing apertured to receive said end andspacing said pin from and seating in one of said members connected bysaid pivot, certain of said bushings seating in said endpieces eachoutside of and engaging a head of one of said bolts for releasablyholding said bolt against axial movement relative to the associatedendpiece, an out-of-round slot in one of said bracket membersnonrotatably receiving a correspondingly configured head of one of saidpins, an adjusting screw threaded into said one bracket in axialalignment with and engaging said head of said one pivot pin foradjusting the friction in said pivots, and means for locking saidadjusting screw in adjusted position.
 5. A pivoted member assemblycomprising a pivoted member, a frame at least partially bounding saidmember and formed of a plurality of releasably connected pieces, boltsreleasably connecting said pieces, a pair of mounting bracket membersattachable to a support, a pair of pivots each pivotally connecting saidpivoted member to one of said bracket members, each of said pivotsincluding a rigid pivot pin having a tapered end and a tough resilientnonmetallic friction bushing receiving said end and spacing said pinfrom and seating in one of said members connected by said pivot, certainof said bushings being seated in said endpieces each outside of andengaging a head of one of said bolts for releasably holding said boltagainst axial movement relative to the associated endpiece, anout-of-round slot in one of said bracket members nonrotatably receivinga correspondingly configured head of one of said pins, and an adjustingscrew threaded into said one bracket in axial alignment with andengaging said head of said one pivot pin for adjusting the friction insaid pivots.